Rosa gene products are ubiquitously expressed at all stages of development. As such, this locus has been widely used for expressing endogenous sequences from endogenous or introduced promoters and for creating transgenic mice, for example from embryonic stem cells. See, e.g., Strathdee et al. (2006) PLoS ONE, Issue 1, e4; Nyabi et al. (2009) Nucl. Acids. Res. 37:e55.
However, conventional methods of targeted insertion can require complicated assembly of target vectors. Thus, there remains a need for methods of targeted insertion into and/or modification of Rosa gene in a targeted fashion. Precisely targeted site-specific cleavage of genomic loci offers an efficient supplement and/or alternative to conventional homologous recombination. Creation of a double-strand break (DSB) increases the frequency of homologous recombination at the targeted locus more than 1000-fold. More simply, the imprecise repair of a site-specific DSB by non-homologous end joining (NHEJ) can also result in gene disruption. Creation of two such DSBs results in deletion of arbitrarily large regions. The modular DNA recognition preferences of zinc-fingers protein allows for the rational design of site-specific multi-finger DNA binding proteins. Fusion of the nuclease domain from the Type II restriction enzyme Fok Ito site-specific zinc-finger proteins allows for the creation of site-specific nucleases. See, for example, United States Patent Publications 20030232410; 20050208489; 20050026157; 20050064474; 20060188987; 20060063231; 20070134796; 2008015164; 20080131962; 2008015996 and International Publication WOs 07/014,275 and 2008/133938, which all describe use of zinc-finger nucleases and which are incorporated by reference in their entireties for all purposes.